UMLS:C0027651 - FACTA Search

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Query: UMLS:C0027651 (tumor)
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Signaling through the receptor for epidermal growth factor receptor (EGFR) is frequently deregulated in solid tumors. Erlotinib (Tarceva, OSI-774, OSI Pharmaceuticals, Inc., Melville, NY) is a low molecular weight, orally bioavailable inhibitor of the EGFR that has been approved for both non-small cell lung cancer and pancreatic cancers. Previous studies have indicated that sensitivity to EGFR antagonists correlated with HER-3 signaling for non-small cell lung cancer. Herein, we have sought to understand the signaling pathways that mediate erlotinib sensitivity for pancreatic and colorectal cancers. In a panel of 12 pancreatic tumor cell lines, we find that EGFR is coexpressed with HER-3 in all cell lines sensitive to erlotinib but not in insensitive cell lines. Erlotinib can block HER-3 phosphorylation in these sensitive cell lines, suggesting that HER-3 is transactivated by EGFR. Knockdown of HER-3 in BxPC3, an erlotinib-sensitive pancreatic tumor cell line, results in inhibition of the phosphorylation for both Akt and S6 and is associated with a decrease in cell proliferation and reduced sensitivity to erlotinib. Therefore, EGFR transactivation of HER-3 mediates Akt signaling and can contribute to erlotinib sensitivity for pancreatic tumors. We extended our analysis to a panel of 13 colorectal tumor cell lines and find that, like pancreatic, HER-3 is coexpressed with EGFR in the most erlotinib-sensitive cell lines but not in erlotinib-insensitive cell lines. These studies suggest that HER-3 could be used as a biomarker to select patients who are most likely to respond to erlotinib therapy.
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PMID:Inactivation of Akt by the epidermal growth factor receptor inhibitor erlotinib is mediated by HER-3 in pancreatic and colorectal tumor cell lines and contributes to erlotinib sensitivity. 1692 26

Erlotinib (Tarceva, OSI-774) is a potent, orally available, small-molecule inhibitor of HER1/EGFR tyrosine-kinase activity. In this study, the antitumor activity of erlotinib was evaluated in two human colorectal tumor xenograft models (LoVo and HCT116) in athymic mice. When erlotinib was administered as monotherapy, significant tumor growth inhibition (TGI) was seen in the LoVo model at both 100 mg/kg [TGI > 100%, P < 0.001; 6/10 partial regressions (PRs)] and 25 mg/kg (TGI = 79%, P < 0.001) doses. However, the HCT116 xenograft model was not responsive to any dose of erlotinib tested. The differential response to erlotinib of these two tumor models was not a result of differences in HER1/EGFR expression levels since these were similar in both cell lines. However, it was demonstrated that resistance to erlotinib in the HCT116 model may be a result of persistent activation of ERK in these tumors. Based on the single agent activity of erlotinib in LoVo tumors, a combination study with CPT-11 (Camptosar, irinotecan) was performed. CPT-11 at the optimal dose of 60 mg/kg or a lower dose of 15 mg/kg resulted in significant TGI (TGI > 100%, P < 0.001, and TGI = 93%, P < 0.001, respectively) in LoVo-bearing mice. Combination treatment with erlotinib (25 mg/kg) and CPT-11 (15 mg/kg) produced significantly greater antitumor activity (TGI > 100%, P < 0.001; 10/10 PRs) than either agent alone (P < 0.05), with no increase in toxicity. These data indicate that erlotinib can enhance the antitumor activity of CPT-11, without enhanced toxicity, in the LoVo human colorectal tumor xenograft model.
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PMID:Antitumor activity of HER1/EGFR tyrosine kinase inhibitor erlotinib, alone and in combination with CPT-11 (irinotecan) in human colorectal cancer xenograft models. 1693 4

Small molecule tyrosine kinase inhibitors (TKIs) are developed to block intracellular signaling pathways in tumor cells, leading to deregulation of key cell functions such as proliferation and differentiation. Over 25 years ago, tyrosine kinases were found to function as oncogenes in animal carcinogenesis; however, only recently TKIs were introduced as anti cancer drugs in human cancer treatment. Tyrosine kinase inhibitors have numerous good qualities. First, in many tumor types they tend to stabilize tumor progression and may create a chronic disease state which is no longer immediately life threatening. Second, side effects are minimal when compared to conventional chemotherapeutic agents. Third, synergistic effects are seen in vitro when TKIs are combined with radiotherapy and/or conventional chemotherapeutic agents. In this article, we will give an update of the tyrosine kinase inhibitors that are currently registered for use or in an advanced stage of development, and we will discuss the future role of TKIs in the treatment of solid tumors. The following TKIs are reviewed: Imatinib (Gleevec/Glivec), Gefitinib (Iressa), Erlotinib (OSI-774, Tarceva), Lapatinib (GW-572016, Tykerb), Canertinib (CI-1033), Sunitinib (SU 11248, Sutent), Zactima (ZD6474), Vatalanib (PTK787/ZK 222584), Sorafenib (Bay 43-9006, Nexavar), and Leflunomide (SU101, Arava).
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PMID:Small molecule tyrosine kinase inhibitors in the treatment of solid tumors: an update of recent developments. 1710 52

The receptor for epidermal growth factor (EGFR) is overexpressed in many cancers. One important signaling pathway regulated by EGFR is the phosphatidylinositol 3'-kinase (PI3K)-phosphoinositide-dependent kinase 1-Akt pathway. Activation of Akt leads to the stimulation of antiapoptotic pathways, promoting cell survival. Akt also regulates the mammalian target of rapamycin (mTOR)-S6K-S6 pathway to control cell growth in response to growth factors and nutrients. Recent reports have shown that the sensitivity of non-small-cell lung cancer cell lines to EGFR inhibitors such as erlotinib (Tarceva, OSI Pharmaceuticals) is dependent on inhibition of the phosphatidylinositol 3'-kinase-phosphoinositide-dependent kinase 1-Akt-mTOR pathway. There can be multiple inputs to this pathway as activity can be regulated by other receptors or upstream mutations. Therefore, inhibiting EGFR alone may not be sufficient for substantial inhibition of all tumor cells, highlighting the need for multipoint intervention. Herein, we sought to determine if rapamycin, an inhibitor of mTOR, could enhance erlotinib sensitivity for cell lines derived from a variety of tissue types (non-small-cell lung, pancreatic, colon, and breast). Erlotinib could inhibit extracellular signal-regulated kinase, Akt, and S6 only in cell lines that were the most sensitive. Rapamycin could fully inhibit S6 in all cell lines, but this was accompanied by activation of Akt phosphorylation. However, combination with erlotinib could down-modulate rapamycin-stimulated Akt activity. Therefore, in select cell lines, inhibition of both S6 and Akt was achieved only with the combination of erlotinib and rapamycin. This produced a synergistic effect on cell growth inhibition, observations that extended in vivo using xenograft models. These results suggest that combining rapamycin with erlotinib might be clinically useful to enhance response to erlotinib.
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PMID:Rapamycin synergizes with the epidermal growth factor receptor inhibitor erlotinib in non-small-cell lung, pancreatic, colon, and breast tumors. 1712 14

The initial diagnosis of lung carcinoma is frequently made by fine-needle aspiration biopsy. Novel therapeutic strategies of this disease include tyrosine kinase inhibitors (TKI), such as gefitinib (Iressa) or erlotinib (Tarceva), which target the kinase domain of epidermal growth factor receptor (EGFR). Somatic mutations of this region have been shown to predict a therapeutic response of lung carcinomas to TKI. EGFR mutations have been described in adenocarcinomas of the lung, especially the bronchioloalveolar subtype, which has both cytopathologic and histopathologic definitions. This study investigates whether tumors with EGFR mutations display a characteristic phenotype on fine-needle aspiration biopsy. We identified 37 fine-needle aspiration biopsy of lung masses on which molecular analysis for EGFR mutations was available. Molecular analysis was performed on DNA isolated from formalin-fixed, paraffin-embedded, or frozen tissue from the corresponding core biopsies/cell blocks or resection specimens followed by PCR with primers for the tyrosine kinase region exons 18-24 and nucleotide sequence analysis by gel electrophoresis. Two observers who were blinded to the mutational data assessed several cytomorphological parameters. A semiquantitative analysis included predominant tissue pattern (flat or overlapping), nuclear features (nucleoli, intranuclear inclusions, grooves), cytoplasmic qualities, and extracellular material. All cases were adenocarcinomas primary in the lung. Thirteen cases showed EGFR mutations in exons 18, 19, 20, or 21 of the tyrosine kinase domain. The 24 cases negative for the relevant mutation served as the control group. Tumors with EGFR mutations were statistically more likely to demonstrate a predominantly flat, monolayer architecture (P=0.04) with nuclear inclusions (P=0.014) and the absence of macronucleoli (P=0.001). The predominance of flat monolayers in conjunction with the absence of extracellular mucin and macronucleoli indicated the presence of EGFR mutations with a positive predictive value of 69% and a negative predictive value of 92%. All four cases with extracellular mucin were negative for the examined mutations. Some of the traditional cytomorphological features of bronchioloalveolar carcinoma, i.e., flat monolayers, intranuclear inclusions, and the absence of macronucleoli, statistically correlated with the presence of mutations within the tyrosine kinase region of EGFR. Cytomorphological features could serve as an adjunctive predictive marker of response to TKIs and possibly to other new therapies in development.
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PMID:Cytomorphological correlates of epidermal growth factor receptor mutations in lung carcinoma. 1742 21

Clinical and animal studies indicate a role for cyclooxygenase-2 (COX-2) and the epidermal growth factor receptor (EGFR) in the development and progression of intestinal polyps and cancers. Although this combination of enzyme inhibition has shown synergy in intestinal polyp and tumor models, the exact mechanism for these effects remains undefined. Therefore, we sought to define the molecular mechanisms through which this process occurs. We observed a significant reduction in the number and size of small intestinal polyps in APC(min+/-) mice treated with either celecoxib (a selective COX-2 inhibitor) or erlotinib (Tarceva, an EGFR inhibitor). However, in combination, there was an overall prevention in the formation of polyps by over 96%. Furthermore, we observed a 70% reduction of colorectal xenograft tumors in mice treated with the combination and microarray analysis revealed genes involved in cell cycle progression were negatively regulated. Although we did not observe significant changes in mRNAs of genes with known apoptotic function, there was a significant increase of apoptosis in tumors from animals treated with the combination. The inhibition of EGFR also induced the down-regulation of COX-2 and further inhibited prostaglandin E2 formation. We observed similar effects on the prevention of intestinal adenomas and reduction of xenograft tumor volume when nonselective COX inhibitors were used in combination with erlotinib. Together, these findings suggest that the inhibition of both COX-2 and EGFR may provide a better therapeutic strategy than either single agent through a combination of decreased cellular proliferation and prostaglandin signaling as well as increased apoptosis.
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PMID:Targeting cyclooxygenase-2 and the epidermal growth factor receptor for the prevention and treatment of intestinal cancer. 1790 47

The Epidermal Growth Factor Receptor (EGFR) family, including EGFR, HER2, HER3, and HER4, is implicated in the development and progression of cancer, and is expressed in many human epithelial malignancies, including Non-Small Cell Lung Cancer (NSCLC). Several molecules were synthesized to inhibit the extracellular domain of EGFR, such as cetuximab (Erbitux), the extracellular domain of HER2, such as trastuzumab (Herceptin) or the EGFR tyrosine kinase domain, such as gefitinib (Iressa) and erlotinib (Tarceva). Gefitinib and erlotinib are orally active, selective EGFR tyrosine-kinase inhibitors (EGFR-TKI) that produce objective response rates in about 10% of advanced NSCLC. More recently, erlotinib produced a significant improvement in survival when compared to placebo in pretreated NSCLCs. Among clinical characteristics, although female gender, and adenocarcinoma histology, showed to be significantly associated to TKI sensitivity, never smoking history is probably the most relevant factor. Presence of specific EGFR gene mutations or EGFR gene amplification confer a particularly sensitive phenotype, and patients with activation of the anti-apoptotic protein Akt are more sensitive, when Akt activation is sustained by a EGFR dependent mechanism. Cetuximab is a human-murine chimeric anti-EGFR IgG monoclonal antibody that has demonstrated both in vitro and in vivo antitumor activity in tumor cell lines expressing EGFR. It has shown impressive activity when combined with radiation by increasing the antitumor effect of radiation therapy. Cetuximab has a synergistic effect with cisplatin and may play a role in reversing resistance to chemotherapy. Cetuximab demonstrated to be active in pretreated NSCLCs, and its activity as first-line therapy in combination with chemotherapy is currently under evaluation. Efforts should be made for the identification of biological mechanism underlying cetuximab sensitivity and emerging data suggest that the drugs is more active in patients with EGFR gene amplification. In NSCLC, trastuzumab produced disappointing results when combined with chemotherapy, but probably patients were not properly selected. Recent findings in gefitinib treated patients support HER2 analysis by fluorescence in situ hybridization as a complementary test for selection of patient candidate for EGFR targeted therapies. Combination of EGFR targeting agents with other biological drugs is under investigation.
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PMID:Epidermal growth factor receptor (EGFR) targeted therapies in non-small cell lung cancer (NSCLC). 1839 76

Human cancer cell lines that can be propagated and manipulated in culture have proven to be excellent models for studying many aspects of gene function in cancer. In addition, they can provide a powerful system for assessing the molecular determinants of sensitivity to anticancer drugs. They have also been used in recent studies to identify genomic alterations and gene expression patterns that provide important insights into the genetic features that distinguish the properties of tumor cells associated with similar histologies. We have established a large repository of human tumor cell lines (>1000) corresponding to a wide variety of tumor types, and we have developed a methodology for profiling the collection for sensitivity to putative anticancer compounds. The rationale for examining tumor cell lines on this relatively large scale reflects accumulating evidence indicating that there is substantial genetic heterogeneity among human tumor cells-even those derived from tumors of similar histologies. Thus, to develop an accurate picture of the molecular determinants of tumorigenesis and response to therapy, it is essential to study the nature of such heterogeneity in a relatively large sample set. Here, we describe the methodologies used to conduct such screens and we describe a "proof-of-concept" screen using the EGFR kinase inhibitor, erlotinib (Tarceva), with a panel of lung cancer lines to demonstrate a correlation between EGFR mutations and drug sensitivity.
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PMID:High-throughput lung cancer cell line screening for genotype-correlated sensitivity to an EGFR kinase inhibitor. 1841 59

The mortality and morbidity of tumors of the upper GI tract are formidable with incidence and mortality nearly the same. Therefore, better therapies are necessary, and these are generally molecularly targeted therapies. This chapter focuses on the treatment of pancreatic cancer with targeted therapy. Important cellular pathways are reviewed, including signal transduction, proteasome inhibition, cell cycle, anti-angiogenesis pathways, immunologic therapies, viral therapy, epigenetic therapies and microarray analysis. Signal transduction pathways include epidermal growth factor receptors, such as cetuximab and Tarceva, as well as other less well-defined pathways. Proteasome inhibition includes inhibition of the 26S proteasome with PS-341. Cell cycle therapies include inhibitors of all the proteins involved in pushing the cell through the cell cycle. Viral therapies mainly cover the adenoviruses, like ONYX-015, and Reolysin, a type 3 serotype Dearing strain with little pathogenicity. Immunological therapies include cytokines, vaccines and cell-based therapies. Epigenetic therapies are mainly centered around histone deacetylases. Microarray analysis analyzes expression of thousands of genes to create a tumor profile, mainly for prognosis or prediction. Various promising treatment strategies are reviewed in terms of treatment with molecularly-guided therapies. Complications of therapy, particularly rash and thrombosis are reviewed.
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PMID:Molecular targeting in pancreatic cancer. 1847 90

Mutational activation of the gene for epidermal growth factor receptor (EGFR) is 1 of the main ways by which this receptor induces non-small cell lung cancers (NSCLC). Variant III EGFR (EGFRvIII) is a potential therapeutic target in NSCLC treatment because of the high frequency of deletion mutations in this protein. This study used noninvasive magnetic resonance imaging (MRI) to investigate the role of an EGFRvIII mutant in lung tumorigenesis and tumor maintenance as well as its response to the EGFR small molecule inhibitor erlotinib (Tarceva) on bitransgenic mice. Both spin-echo and gradient-echo sequences with and without cardiac and respiratory gating were performed to image the invasive mouse lung tumor driven by EGFRvIII mutation. Tumor volumes were measured based on 2-dimensional axial MRI; 3-dimensional rendering of the images were obtained to demonstrate the spatial location and distribution of the tumor in the lung. The MRI results indicated that the tumor driven by the EGFRvIII mutation was generated and maintained in the bitransgenic mice with the use of doxycycline. Tumor monitoring via MRI showed that Erlotinib can significantly inhibit the growth of tumor in vivo. MRI has the ability to image mouse lung tumor with different sequences focusing on tissue contrasts between tumor and surroundings. The MRI approaches in this work can be applied on other antitumor drug treatment evaluation in vivo when appropriate sequences are chosen.
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PMID:Magnetic resonance imaging of the response of a mouse model of non-small cell lung cancer to tyrosine kinase inhibitor treatment. 1858 70

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